It's hard to distinguish between Majid “Chi” Hasan and Sean “Face” Foote's voices on the phone. But the nuances are there: Face speaks in a rich baritone with a slight New York inflection, and Chi speaks in a tenor with Southern and Midwestern cues on the tails of his sentences.

As The Horsemen, an Atlanta-based production duo, they share a singular sound. After six years of collaboration, they flow in and out of sessions with a versatile vocabulary that spans from the thick tumbleweeds of dirty Southern style to the depths of lush, orchestral soul to offbeat Norwegian R&B. It's a sound Mary J. Blige liked so much, she went to bat for them to clear a sample on one of the songs The Horsemen produced for her. “Working with Mary, she really was married to the track,” Face says. “It was a Barry White sample. They were having problems clearing it, and she wouldn't have it any other way.”

Making a track for Blige on a blown-out MPC2000XL was a crowning moment for The Horsemen. “After we did the track, we brought in a live orchestra band to enhance the synth sounds. Besides the fact that she's a legend, an icon, any producer that's about to get on Mary's album, that's a credit card for 10 more years of work,” Chi says.

From reading the duo's resume, a Røde NT2000 mic, a Roland Fantom XR sound module and a Yamaha Motif keyboard seem like unlikely tools for two business professionals. Both went from business school and Corporate America to the recording studio.

“One of the technical standpoints about doing music is not from the studio standpoint, it's from your business standpoint — knowing how publishing works,” Face says. Much of their big-business sense applies to their small-business philosophy. It's what made Twista, Mase and Jennifer Lopez some of their top clients.

“I think Chi is better musically on the keys than I am,” Face admits. Meanwhile, Chi is likewise complimentary to his cohort, calling Face the “sampling king.”

Barry White, Isaac Hayes, Curtis Mayfield and Millie Jackson provide some of their favorite vinyl snippets. “I sample everything into Cool Edit Pro and chop it up,” Face says. “Then I take it to ReCycle and then to Reason.” Face's sampling process sometimes takes another route as well. “We might also start off with a bass loop in Pro Tools LE 6.4 and import that into the MPC to give it a big sound, and then we'll add music from the Korg Karma.”

The Horsemen bring different flavors to the studio. Face hails from Antigua, growing up with steel-drum tones attuned to the Caribbean culture, but he spent much of his youth in New York. “My influence in New York was a street-hard sound. [Chi] grew up in Florida and Chicago, so he was exposed to bass music and house music. A lot of times when we're working on a track, he'll want to put the 808 on it.”

Part of the duo's secret to making a wide range of music is mood, like using brighter sounds for R&B. “With a bright sound, we use a mid-level string from the upper keys because they ride melodic,” Chi says. “A dark sound tends to be more of a brass on the low end of the keyboard, and that's giving you a gritty, dirty, street brick-project sound. With a dark sound, you can hold the note on the low end.”

Face and Chi often go for a thick sound, musicwise. “We do a lot of layering,” Face says. “If you play a brass sound, we might add a synth on it and then make the sound more full in Reason.”

“You can actually have 16 sounds that make one note,” Chi adds.

Face and Chi are also chiming in unison. So far this year, they're bringing beats for Kujo Goodie, Outlawz, Fabolous, an MTV score and their own artist named Certified — and the gates are barely open.